list = [n+m+z for n in "ABC" for m in "XYZ" for z in "123"]

L1 = ['Hello', 'World', 18, 'Apple', None]
L2 = [s.lower() if isinstance(s, str) else s for s in L1]
for s in L2:
    if not isinstance(s, str):
        L2.remove(s)
print(len(str(pow(2, 10))))
print(2 ** 10)